Professors Holmes and Watson
by Jack HasSpareTime
Summary: A Johnlock Potterlock AU. Rated T because I may or may not throw smut in eventually. Professor Watson is on the Hogwarts Express on the first day of school, as he does every year. This year, a new person enters the train compartment, Mr. Sherlock Holmes.
1. Chapter 1

The train gave a whistle and departed Platform 9 and 3/4. John Watson sat in one of the few empty compartments in the train, reviewing his lesson plans for the first week of school. He reread and muttered things to himself, occasionally taking a quill and editing something.

Another person entered the compartment, making John look up. He was greeted by a tall man with dark curly hair and striking colorful eyes. The other man said nothing and simply sat down across from Watson, but not in the usual way. He lay down on the bench with his feet up and his hands pressed together under his chin.

"Hello," said John.

No answer from the new passenger.

"I said hello." Watson was slightly louder this time.

The mysterious man turned his head and looked at John as if noticing him for the first time. "Afternoon," he said, then resumed his previous position.

"Might I ask who you are?"

The man sighed and sat up, as if realizing and dreading he would actually have to converse. "The name is Sherlock Holmes." Sherlock extended a hand.

"Professor John Watson." He grabbed the hand and firmly shook it.

"I'm curious," said Sherlock. "How many years did you serve as an Auror before turning to teaching?"

"Seven. Wait-"

"And what drew you to Defense Against the Dark Arts when you have a natural knack for Transfiguration?"

John took a second to turn that over in his head, make sure he heard it right. "Pardon?"

"Well I can see your lesson plans to start, which gave away the subject you teach. The Transfiguration bit I figured out through your wand. Around 10 1/2 inches typically indicates a strength in that field. The fact that you were an Auror is evident in your posture and hair, prematurely growing gray and proud posture. This is an indicator of extreme duress, and I noticed a small scar on your hand, no doubt from something slightly dangerous at least. That's not all though, you felt the need to introduce yourself immediately. Most people would've ignored the random man who came into their car, but as an Auror, it would be in your nature to not only be curious, but to glean some information from this stranger." Sherlock sat back in his seat, clearly pleased with himself.

Professor Watson blinked. "You figured all of that out from a single look?"

"Among other things."

"Interesting. Well, you know me now, but I haven't the faintest idea about you. What do you teach?"

"I'm the new Potions Master this year." Unless he was explaining his insane ideas, Sherlock seemed to like to keep things short.

"And what did you do before that?"

"I had a job in the Weasley Dragon Reserve in Romania."

"And you've decided to come to Hogwarts why?" Dragons to Potions Master was a pretty enormous job change.

"I got bored," Sherlock replied and shrugged as if that were perfectly normal.

This man was ludicrous. John sat forward, elbows on his thighs. "Bored? By dragons?"

Sherlock leaned in, "It wasn't really so much that I was bored, more that Mr. Weasley was sick of my-"

"Candy trolley!" interrupted a voice. Mrs. Hudson, the school nurse who liked to help out wherever she could, leaned into their little compartment. The boys immediately sat up straight.

"None for me, thanks," asserted John.

"Some Bertie Bott's Every Flavor Beans," said Sherlock, pulling out 5 knuts and handing them to the older lady. "Please."

Mrs. Hudson accepted the coins and dug around in her cart. She drew out a small purple box and handed it to Sherlock. "There you go, dear," she said sweetly. Then she smiled and continued down the isle.

Sherlock opened the box and poured the contents into his hand. He looked at them all, shifting some out of the way to view others, then picked one out and proceeded dump the rest in his mouth. After chewing and swallowing, he held up the rejected bean. "Liver," he announced proudly.

John laughed. "I don't believe you."

"Care to test that?" Sherlock extended an open hand to John, the bean sitting in the middle like it was something of huge importance.

John plucked the candy from Sherlock's hand and made a show of dropping it in his mouth. He began to chew and quickly discovered the taste. It was liver. He wouldn't let Sherlock know though, and did not speak nor make an expression until he swallowed. "That wasn't so bad. Chocolate."

"Lie."

"Pardon?"

"You're lying. I can tell."

John sighed. "Of course you can. That was bloody disgusting."

Sherlock laughed smugly, a light and low-pitched laugh that for some reason coerced John into laughing too. It was cut off quickly by the whistle indicating that the train was about to arrive at the school. John glanced down at his clothes, a ratty old sweater and khaki pants. He stood up. "I suppose I ought to go change. See you in the Great Hall, Mr. Holmes."


	2. Chapter 2

John took his usual place in the great hall, 3rd away from Headmaster Lestrade, in between the divination teacher, Sally Donovan, and the space of the potions master, whose spot remained empty. Honestly, for the first day of school, it was drearier than usual. Of course the plates and trays in front of them were all empty, but the sky was far from that. Looking up, one would see a vicious storm. It only showed during flashes of white lightning illuminating the falling rain and swirling clouds. the only constant was the aggressive pounding on the roof and against the windows. However, the floating candles didn't seem to be affected by the mood of the weather; in fact, their flames danced a bit higher than normal. The weather didn't seem to bother the kids much either, who were only groaning about the lack of food. Headmaster Lestrade calmly sat back in his chair, which was placed behind the plain old stool with that old ratty hat sitting on it.

In came Ms. Molly Hooper, like every year, leading all of the first years in rows of two. Sherlock and the gamekeeper, Sebastian Moran, came in behind them, making sure there were no stragglers. The first years had mixed looks of nervousness and confidence as they calmly kept together. Some were even holding hands. John noticed one curly-haired boy out of the forty or so standing between Holmes and Moran, in avid conversation with both of them. As the first years stood in front of the stool and Professor Hooper took the stage. Sebastian and Sherlock left and came around the tables to seat themselves.

Sherlock smoothly slid into his seat next to John. He was still wearing the same coat and scarf he had been on the train. John however, was now wearing a suit as opposed to the sweaters he preferred. They shared a mutual nod, but no other greeting as Lestrade stood up and started the ceremony.

"A few beginning of the year announcements," he said. "First years, as always, take notice that the Dark Forest is strictly off limits. Miss Anthea would also likely to tell you that the 3rd Floor corridor on the right side is to be treated the same way. Avoid it. Thanks. Ms. Hooper, if you would."

She cleared her throat. "When I call your name, please come and sit on this stool. The Sorting Hat will be placed on your head and you will be sorted accordingly." Molly unfurled the scroll and read the first name. "Mallory Amiston."

A small girl skipped up to the stool and sat down. Molly set the hat on her head. It was a few seconds before it decided "Hufflepuff!"

More names were called and more children were sorted. So far, by John's count, there were 5 Gryffindors, 3 Slytherins, 7 Hufflepuffs, and 4 Ravenclaws. Then Molly called, "Archibald Smith."

The little boy whom Sherlock and Sebastian had been conversing with calmly walked up to the stool and seated himself on it. Sherlock became noticably more interested. The Sorting Hat appeared to be taking it's time, study Archie's mind carefully. After about a minute of the hall silent in anticipation, the hat announced "Gryiffindor!"

The Potions Master sat back in his chair as Archie hopped off the stool and joined his fellow Gryffindors at their table. More names were called. The totals ended up being 9 Gryffindors, 12 Hufflepuffs, 10 Ravenclaws, and 13 Slytherins.

Now Molly went and took her seat next to the headmaster. She tapped on her goblet with her fork for the student's attention. Lestrade stood. "Let the feast commence."

The plates filled with food and they all began to eat. The titter of the student's voices was loud, almost overwhelming. The first years were welcoming and introducing themselves to each other and returning students were reuniting. John couldn't help but smile at them. He turned to Sherlock. "So what house were you in?"

"I was a Ravenclaw."

"I was a Gryffindor. I suppose that's why they made me head of that house," he chuckled. "Do you remember this first day? The wonder and excitement?"

"It was quite interesting indeed. I remember that that arse of a ghost, Peeves, harassed me all evening."

"Oh." Awkward. John changed the subject. "What was your strength?"

"Always potions. I had a knack for chemistry."

"Chemistry?" John hadn't heard this term before.

"I'm muggleborn. Back in the regular world, it was a branch of science dealing with reactions and substances. It was quite different from the results of magical elixirs, but once you figure out-"

"Wait, you're muggleborn?" chimed in another professor. "Wow. You're the first muggleborn teacher we've ever had here!" He excitedly shook Sherlock's hand. "Phillip Anderson. Muggle Studies."

"Sherlock Holmes. Potions," he replied through gritted teeth.

"You'll just have to tell me everything! Muggle sciences has always been something of interest to me-."

"Anderson. Please, you're rather annoying."

John chuckled a bit as Anderson looked flustered. "Alright then," said the Muggle Studies teacher, returning to his seat.

"That was rather rude, Sherlock," said John.

"Who cares? Now, what are the names of all of the teachers here so we can avoid more introductions?"

"Well," John pointed at a woman in the back of the hall, standing firmly with her arms crossed. "That's Miss Anthea. She's a caretaker for the students, making sure they aren't in the halls after curfew and such." He pointed at the short man at the other end of the table. "Jim Moriarty teaches Charms. He's also head of Slytherin." Then he went down the line. "Irene Adler, Physical Education. Janine Hawkins is our current Arithmancy professor. The lady next to her is Mrs. Hudson, whom you met on the trolly. She's the school nurse, but also head of Hufflepuff. That old dear would be loyal to the end, bless her. Next to her is William Wiggins, who teaches alchemy. Mycroft Holmes is the current Astronomy teacher, but everyone is pretty sure he's practically in charge of the school. Wait- Holmes. Is that your brother?"

"Sadly, yes," Sherlock sighed.

"Anyway, he's seated next to Headmaster Lestrade. Next to him is Ms. Molly Hooper, a lovely lady who teaches Transfiguration. This lovely lady next to me is Sally Donovan, who teaches Divination."

Sally squinted skeptically at Sherlock. "Nice to meet you."

"Now if you look to your right, you'll meet Kitty Reily. She's the Magic Theory teacher."

"Pleasure to meet you Mr. Holmes," she said. Her voice had that slippery snake-like quality to it.

"I can't quite say that the feeling is reciprocated," said Sherlock. He turned back to John. "And we've met the imbecilic Anderson."

"Yup. He's head of Ravenclaw. Next to him is someone else you've already met. That's Sebastian Moran, gamekeeper and in charge of Care of Magical Creatures. Next to him is Soo Lin Yao, History of Magic. Andy Galbraith, the man who is blatantly staring at her, is the Astronomy teacher. Angelo teaches Herbology. That's every one."

"Interesting," mused Sherlock. "It would appear there are two pairs of teachers sleeping with each other. One pair who _wants_ to. The gamekeeper has also been convicted of multiple teacher is jealous of your job, despite the curse on the subject that has not seemed to hit you yet. There are also multiple former Aurors and all are alumni of this school. One of them has an incredibly bad rash in a less than satisfactory place and another doesn't like the pumpkin juice that appears in the goblets."

"That all?"

"No not nearly. It's just the basics."

"Incredible! I can see quite clearly why you were Ravenclaw."

Sherlock shyly smiled at the praise. "That's not how people typically react."

"Well then you aren't talking to the right kind of people." John grinned. "You know, I can tell we'll be good friends, you and I." _Maybe something more._ he added in his head.


	3. Chapter 3

"Good morning, class!" greeted John. "Welcome to Defense Against the Dark Arts for First Years. I'll be your teacher, Professor Watson. Right now, basic rules..."

A student raised their hand. The professor was prepared to deal either with the smartass, the idiot, or the overly enthusiastic one. "Yes. Miss..."

"Georgina. Georgina Craig."

"Alright, Georgina. What is your question?"

"I seem to be in the wrong class." She waved her schedule in the air. "It says room 122, but it says I have Potions with Mr. Holmes."

"Ah that would be room 221," replied Watson. "Turn right outside the door, down the hall, down the stairs, to the left. Anyone else in the wrong classroom?"

Five more students stood up and followed Georgina out of the room. John rolled his eyes. "Now that that's settled; let's go over some rules. I shouldn't see you touching your wands unless we are practicing. Raise your hand to speak. No fighting. Remember that and we should all get along nicely. And you all know how house points work."

He gave them a beat to take in the information. "Okay. Now open your books to page 3. Today we'll be learning the most basic and important spell to know against a foe: expelliarmus."

The eager little first years took out their books and readied their quills. "Now, the most important thing to know about expelliarmus," continued John, "is that even though it seems only a simple disarming spell, it's more than that. This spell has brought down many dark lords and is not to be meaninglessly tossed around." Some of the kids were completely zoned out, others jotting notes, and others were staring at their professor, hanging on to his every word in fascination. _Muggleborns._ thought John.

He had to admit that might be his favorite thing about teaching magic may be the muggleborns, or at least the muggle-raised. Pure-bloods and the majority of half-bloods were raised around magic their entire lives. This was dull to them. The ones who came from the muggle world were absolutely captivated by it. Their eyes lit up with wonder whenever they learned something new. That simple little bit of awe made John proud to be an educator.

"A number of factors should be taken into account when practicing the spell; the first being strength. Not the strength of the wizard, but the strength you want it to be. You're not going to put as much force behind knocking a wand out of someone's hand as you would be throwing them across the room." John noticed a boy in the back with his hand up. "Yes, um-" John waved his hand, prompting for the child to say his name.

"Micheal. Or Mickey if you prefer, sir."

"Mickey, alright. Your question?"

"Shouldn't we first learn about the Dark Arts before we act against them?"

There's the smart ass. "It's not just _Against _the Dark Arts is _Defense Against _the Dark Arts. I'm merely teaching you first the most important self-defense spell there is."

"You just said it could throw someone across the room. That seems more offensive than defensive."

John rolled his eyes. "Okay. Stand up, Mickey."

Warily Mickey stood up and walked out from behind his table. "Right. Pick up your wand." He did. "Now come at me!" said John.

The poor kid stood frozen to the spot. John had to coax him. "Come on! Free jab at the teacher! You might not get another opportunity!"

Mickey started walking towards the professor and then began running, wielding his wand more like a club than a tool.

"Expelliarmus!" shouted John. A blast of red light shot from his wand and knocked Mickey's right out his hand, careful not to hit the student.

"Hey, no fair!"

"I was defending myself. Now sit down."

The student picked up his wand and went and sat down in a huff. "Now that was a small casting. A big casting would be something like this." John pointed his wand at a chest he'd conveniently placed in the class room. "Expelliarmus!"

The chest flew across the room and hit the wall. "Okay everyone, pick up your wands- careful Mickey- you'll take someone's eye out! We're going outside in the courtyard, where I have targets set up for you to practice. Come now everyone, let's go."

"Alright class!" said Sherlock. "Right away I'd like to establish that this will not be your easiest class. I expect nothing but the most attention and nothing but the best results-"

Just then six students walked in the door. "Is this Mr. Holmes's class?"

"I suspect you came from Defense Against the Dark Arts. Bloody scheduling mistakes. Take your seats now. As I was saying before, I expect attention and results. Lateness from this point onward will have definite consequences, unless you have an actual meaningful excuse, which I doubt you will. Don't you dare try to pull anything either; I guarantee you will be caught. House points will be rewarded for participation and high marks. They'll be deducted for interruptions and other annoyances. Low grades will not take away house points, merely earn my disappointment and mandatory tutoring sessions. Understood?"

There was a chorus of mumbled "Yes, Mr. Holmes."

"I am your teacher, not your best friend. Now, can anyone tell me the first thing any proper chemi-" he caught himself. "_potions maker _needs first, before he or she or they can even begin properly brewing a potion?

One of the girls who came in late raised her hand. Her hair was died brunette and she looked much more eager than most students. "You." Sherlock pointed. " Miss..."

"Georgina Craig," she announced proudly.

"Yes, Miss Craig. Now answer the question."

"You'd need to have all the proper materials and ingredients gathered."

"You're on the right track, but there's something else."

Archie, who was sitting in the back, tentatively raised his hand. Sherlock smiled. "Yes."

"You need a state of mental readiness."

Sherlock clapped his hands. "There we are! I hope you wrote that down. The first thing you need before brewing a potion..." He turned around and excitedly wrote at the top of the chalkboard. "is mental. readiness." He underlined each word.

"How are we mentally ready, Mr. Holmes?" asked another girl in the class.

"I was getting to that- um-"

"Haley."

"Haley. Yes right. Don't expect me to remember your names. Maybe I'll make name tags for your desks... Anyway let's go around the room. Ways that we can reach a state of mental readiness! Go!"

"Know the recipe?" suggested one boy.

"Yes!" Sherlock beamed and made a circle motion with his hand. "Keep going."

"Be calm!" shouted another.

"Yes!"

"Be careful!"

"Have an objective?"

"Be confident!"

"Yes! Yes! And yes!" exclaimed Sherlock, absolutely elated. "By far you are the most competent bunch of students I've ever had. Congratulations. The rest of the semester should go smoothly." _Hopefully. _he added mentally.


End file.
